Thermometer



May 31, 1932. c. s. RUCKSTUHL THERMOMETER Filed April 23, 1927 Patented May '31, 1932 UNITED STATES CHARLES S. Rfi'GKSTUHIk, OF ST. LOUIS, MISSOURI 'rnnniaomnrna Application filed April 23,

My invention relates to thermometers of the kind commonly designated as fever thermometers. In the thermometers described in Letters Patent No. 1,034,735 granted to me August 6, 1912, the stem of the thermometer is of triangular or prismatic shape with one of its edges rounded into a lens and with one of the sides adjacent to the lens engraved with a suitable scale; and in order to facilitate reading of the thermometer, the lens is outlined by two longitudinal grooves in the adjacent sides of the prism, which grooves are partlyfilled with suitable coloring matter, preferably red. The thermometer thus de- 5 scribed is easily readable and very satisfactory; but the cost of engraving the longi' tudinal grooves and applying the coloring matter adds about fifty per cent to the total cost thereof; and such coloring matter is in the course of time liable to disappear through the continual using and cleansingof the thermometer. The purpose of the present invention is to obtain the advantages of my former thermometer at a relatively small cost and in such a manner that the coloring matter will be fully protected. r In the accompanying drawings, wherein like symbols refer to like parts wherever they occur, Fig. 1 is an edge view of the tubing used in the manufacture of my new thermometer; Fig. 2 is a cross, section through such tub- 111g;

Fig. 3 is a front edge view of my improved thermometer;

Fig; 4 is a side view thereof; and

Fig. 5 is an enlarged cross-sectional view. In the manufacture of thermometers, the glass is worked into long tubes, which are 40 broken off into blanks or sections of suitable length for thermometer stems. These blank stems are left open at both ends; and the bulb is applied to one end and filled with mercury;

and the other end of the stem is then sealed 7 and the scale is engraved on the side of the 1927. Serial No. 185,947.

stem. In the manufacture of thermometers according to my Patent No. 1,034,735, the longitudinal lines were engraved and thecoloring, matter applied thereto after the closing-of the stem, these operations being 59 expensive on account of requiring skilled labor and involving'risk of breakage.

According to the present invention the formation of the colored lines that delimit the lens, is simultaneous with the manufacture of the stem tubing. For this purpose, two relatively small masses of red or other suitably colored glass are suitably worked into the main body of glass prior to its passage through the die and formation into tubing, such added masses being properly positioned with reference to the die, to be drawn out into two colored lines 11 on either side of the lens or rounded edge 12 of the prism of the stem tubing 13. In consequence of this location of the lines of colored glass, they delimit or outline the lens or rounded edge 12 of the tubing. The tubing,

with its colored lines' on either side of its rounded edge, is broken into suitable lengths or blanks for thermometer stems, and the thermometers are made therefrom by adding the bulb l4, inserting the mercury, engraving the scale 15 and closing the end of the stem.

As the tubing is I made in considerable lengths, the cost of forming the colored lines A thermometer comprising a sector shaped stem with its apical edge formed into a lens and having embedded therein narrow flat bands of colored glass which extend substantially parallel with the flat sides of said stem throughout the length of said stem, the front margins of said bands outlining said apical lens and the rear margins located short of lines extending from the mercury thread perpendicularly to the flat sides of said stem, said narrow bands constituting the only obstruction to light through the flat sides of said stem.

Signed at St. Louis, Missouri, this th day of April, 1927. a, n 16 CHARLES S. RUCKS TUHL. 

